Neuronal memory allocation

Memory allocation is a process that determines which specific synapses and neurons in a neural network will store a given memory.[1][2][3] Although multiple neurons can receive a stimulus, only a subset of the neurons will induce the necessary plasticity for memory encoding. The selection of this subset of neurons is termed neuronal allocation. Similarly, multiple synapses can be activated by a given set of inputs, but specific mechanisms determine which synapses actually go on to encode the memory, and this process is referred to as synaptic allocation. Memory allocation was first discovered in the lateral amygdala by Sheena Josselyn and colleagues in Alcino J. Silva's laboratory.[4]

At the neuronal level, cells with higher levels of excitability (for example lower slow afterhyperpolarization[5]) are more likely to be recruited into a memory trace, and substantial evidence exists implicating the cellular transcription factor CREB (cyclic AMP responsive element-binding protein) in this process.[5][6] Certain synapses on recruited neurons are more likely to undergo an enhancement of synaptic strength (known as Long-term potentiation (LTP))[7] and proposed mechanisms that might contribute to allocation at the synaptic level include synaptic tagging, capture, and synaptic clustering.[3]

  1. ^ Won, J. and A.J. Silva, Molecular and cellular mechanisms of memory allocation in neuronetworks. Neurobiol Learn Mem, 2007. PMC 2673809
  2. ^ Silva, A.J., Zhou, Y, Rogerson, T, Shobe, J and Balaji, J. Molecular and Cellular Approaches to Memory Allocation in Neural Circuits. Science, Oct 16 2009;326(5951):391-5. PMID 19833959.
  3. ^ a b Rogerson, T. et al. Synaptic tagging during memory allocation. Nature Rev. Neurosci 15, 157-169 (2014)
  4. ^ Cite error: The named reference Han2007 was invoked but never defined (see the help page).
  5. ^ a b Zhou, Y., Won, J., Karlsson, M. G., Zhou, M., Rogerson, T., Balaji, J., ... & Silva, A. J. (2009). CREB regulates excitability and the allocation of memory to subsets of neurons in the amygdala. Nature neuroscience, 12(11), 1438-1443.
  6. ^ Yiu, A. P. et al. Neurons Are Recruited to a Memory Trace Based on Relative Neuronal Excitability Immediately before Training. Neuron 83, 722-735 (2014)
  7. ^ Bliss, T. V., & Collingridge, G. L. (1993). A synaptic model of memory: long-term potentiation in the hippocampus. Nature, 361(6407), 31-39.